More and more mobile computing devices become commonplace in every day life. Such mobile computing devices include cell phones, personal digital assistance (PDA) and notebooks all of which have achieved a high penetration rate in modern society. With such mobile computing devices it has become of interest to discover computing services, for example, in the geographical vicinity of the current location of the mobile computing device. In this respect context-based services may be, for example, location-based services or, for example, time-based services. Location-based services include printing services, weather forecast applications, travel guidance, assistance and emergency services for example.
Context-based service look up takes place in a system comprising a service consumer being represented by, for example, a mobile computing device, further comprising a service provider and a registry server. The service consumer looks up services in the registry server and consumes service functionality by invoking operations on a service instance. The service provider publishes service instances on the registry server for look up.
A service is an abstract entity encapsulating functional behaviour accessible via a well-defined service interface. A service has a service type, which defines a set of named operations, the generic semantics, and the abstract input and output messages.
A service instance is a concrete entity implementing a service. Associated with a service instance is a set of attributes describing additional aspects of the service. Binding information is a set of mandatory attributes and describes the service instances, for example an access point in terms of network address, protocol and messages format. Additional attributes may be service qualifiers, which further differentiate service instances.
The service consumer looking up a service is situated in some context. This context may be expressed by a set of attributes, which may be referred to as context qualifiers. The set of all context qualifiers applicable to the service consumer is its situation. The set of all context qualifiers applicable to a particular service instance is the service instance's scope.
Context-based service look up is the process of matching a service consumer's situation with the published service instances' scopes. A match occurs, if the service consumer situation is within a service instance's scope.
Under “http://www.cs.usy.ac.cy/courses/EPL603/gini-3.ppt” a presentation is made available to the public concerning the matching of object-oriented data structures, in particular Java objects. It discloses an example printer attribute location (floor, “3”, “1234”, building “A1”).
It is a challenge to provide a method for a context-based service look up, which enables an efficient context-based service look up. It is further a challenge to provide a device for a context-based service look up which enables an efficient context-based service look up.